Surveys of Food Intake Just after the Nuclear Accident at the Fukushima Daiichi Nuclear Power Station.

Massive release of radioactive materials into the atmosphere occurred due to the Fukushima Daiichi Nuclear Power Station (FDNPS) accident in March 2011. The World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported the results of dose estimation to assess the health effect of the accident and both reports state that their assessments of internal and external exposure doses contain certain uncertainties due to uncertainties inherent to the basic data. Therefore, estimation of the internal dose from tap water was conducted in this study by utilizing a database of deposition calculated by an atmospheric transfer, dispersion and deposition model (ATDM) in conjunction with the newly obtained data on the volume of daily water intake obtained by a web-based survey. The median mean and 95-percentile of thyroid equivalent doses were estimated for 1-year and 10-year children and adults in 12 municipalities in the evacuation area in Fukushima prefecture. The present mean thyroid dose estimations for 1-year children (0.4–16.2 mSv) are smaller than the corresponding values in the UNSCEAR 2013 report (1.9–49 mGy). Dose-modifying factors in the Japanese or local community are discussed.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) established by the General Assembly in 1955 assesses the levels and effects of exposure to ionizing radiation on human health and the environment. This is the second of four volumes of scientific annexes that provides the supporting scientific deliberations for the UNSCEAR 2020/2021 report to the United Nations General Assembly. Annex B “Levels and effects of radiation exposure due to the accident at the Fukushima Daiichi Nuclear Power Station: implications of information published since the UNSCEAR 2013 Report” summarizes all relevant scientific information (peer reviewed literature and monitoring data) available up to the end of 2019. These data relate to the levels and effects of radiation exposure due to the accident at the Fukushima Daiichi Nuclear Power Station. The aim of the report is to provide a summary of all scientific information and an appraisal of the implications of this information for the UNSCEAR 2013 Report.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) established by the General Assembly in 1955 assesses the levels and effects of exposure to ionizing radiation on human health and the environment. This is the second of four volumes of scientific annexes that provides the supporting scientific deliberations for the UNSCEAR 2020/2021 report to the United Nations General Assembly. Annex B "Levels and effects of radiation exposure due to the accident at the Fukushima Daiichi Nuclear Power Station: implications of information published since the UNSCEAR 2013 Report" summarizes all relevant scientific information (peer reviewed literature and monitoring data) available up to the end of 2019. These data relate to the levels and effects of radiation exposure due to the accident at the Fukushima Daiichi Nuclear Power Station. The aim of the report is to provide a summary of all scientific information and an appraisal of the implications of this information for the UNSCEAR 2013 Report.

As the next step that occurred more than one decade after the accident at the Fukushima Dai‐ichi Nuclear Power Station (FDNPS), decontamination and demolition have been carried out in the Specified Reconstruction and Revitalization Base (SRRB) of the difficult‐to‐return zone around the FDNPS. However, the risk of internal exposure among workers due to airborne dust inhalation after building demolition operations has not been sufficiently evaluated. To evaluate the working environment and internal exposure risk due to inhalation in the SRRB of Tomioka town, Fukushima Prefecture, the cesium‐137 (137Cs) radioactivity levels in the airborne dust at building demolition sites were analyzed using gamma spectrometry. The 137Cs radioactivity levels and resuspension factors of the airborne dust at the subject building sites in the difficult‐to‐return zone remained at high levels compared with those of the control, which was located in the evacuation order‐lifted area in Tomioka town. However, the 137Cs radioactivity levels did not increase significantly, despite demolition operations that used heavy machinery. In this case, no substantial increases in accident‐derived 137Cs levels due to decontamination and demolition in the SRRB of Tomioka town, Fukushima Prefecture, were observed in the airborne dust samples, which suggests that the 137Cs radioactivity in the airborne dust is primarily associated with particles that are resuspended by localized winds accompanied by the transfer of construction vehicles as opposed to the decontamination and demolition operations. However, the internal exposure doses due to aspirating airborne dust containing 137Cs were extremely low compared with the estimated annual effective doses of decontamination workers or the limits recommended by the Japanese government. Additionally, countermeasures such as wearing protective masks could help reduce the on‐site inhalation of soil‐derived radionuclides. Integr Environ Assess Manag 2022;18:1555–1563. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

The identification of thyroid cancers among children after the Chernobyl nuclear power plant accident propelled concerns regarding long-term radiation effects on thyroid cancer in children affected by the Fukushima Daiichi nuclear power plant accident in Fukushima, Japan. Herein we consider the potential association between absorbed dose in the thyroid and the risk of developing thyroid cancer as detected by ultrasonography on 300 473 children and adolescents aged 0–18 years in Fukushima. The absorbed dose mentioned in the present study indicates the sum of that from external exposure and that from internally deposited radionuclides. We grouped participants according to estimated absorbed doses in each of 59 municipalities in Fukushima Prefecture, based on The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report. The 59 municipalities were assigned to quartiles by dose. We limited our analyses to participants aged ≥6 years because only one case of thyroid cancer was observed in participants aged ≤5 years; 164 299 participants were included in the final analysis. Compared with the lowest dose quartile, the age- and sex-adjusted rate ratios (95% confidence intervals) for the low-middle, high-middle and highest quartiles were 2.00 (0.84–4.80), 1.34 (0.50–3.59) and 1.42 (0.55–3.67) for the 6–14-year-old groups and 1.99 (0.70–5.70), 0.54 (0.13–2.31) and 0.51 (0.12–2.15) for the >15-year-old group, respectively. No dose-dependent pattern emerged from the geographical distribution of absorbed doses by municipality, as estimated by UNSCEAR, and the detection of thyroid cancer among participants within 4–6 years after the accident. Ongoing surveillance might further clarify the effects of low-dose radiation exposure on thyroid cancer in Fukushima.

R&D of JAEA for the decommissioning of TEPCO's Fukushima Daiichi nuclear power station.

There has been an increase in lifestyle-related diseases in Fukushima Prefecture since the Great East Japan Earthquake. However, the overall long-term trends of lifestyle-related diseases in the Fukushima Prefecture according to the evacuation and other area are not reported. Therefore, we examined the long-term trends in the prevalence of metabolic syndrome before and after the Great East Japan Earthquake in Fukushima Prefecture according to these areas using a national database. The target population was approximately 330,000–440,000 per year; Fukushima Prefecture residents aged 40–74 years who underwent specific health check-ups during 2008–2017 participated in the study. Fukushima was divided into mountainous, central, coastal and evacuation areas. Using the Poisson regression model, the prevalence of metabolic syndrome in each fiscal year was determined by gender and age group for each location and compared before and after the disaster as well as between areas. Prevalence increased significantly throughout the observation period, particularly in the evacuation area. Age- and gender-adjusted prevalence rates significantly increased from 16.2% in 2010 to 19.5% in 2012 (prevalence ratios = 1.21) and 20.4% in 2017 in the evacuation area. Among other areas, coastal areas showed the highest increase with 17.9% (2017), followed by central areas with 16.5% (2017) and mountainous areas with 18.3% (2016). These increases were particularly high among men and the elderly. The prevalence of metabolic syndrome increased rapidly after the disaster, especially in evacuation area, and continued for subsequent 6–7 year. Long-term monitoring and measures to prevent lifestyle-related diseases are needed after major disasters, especially in evacuation areas, among men and the elderly.

Risks from CT scans—what do recent studies tell us?

Background: Thyroid cancer incidence of individual dose groups in Fukushima residents exposed at ≤18 years of age demonstrated a linear response to thyroid dose estimated in the United Nations Scientific Committee on the effects of Atomic Radiation (UNSCEAR) 2020/2021. Increased childhood thyroid cancer in Fukushima was found to come dominantly from radiation exposure from the nuclear accident. The UNSCEAR 2020/2021 concluded that the apparent excess of thyroid cancers would not be expected at thyroid doses estimated by the UNSCEAR. The purpose of this paper is to solve the puzzle of the high childhood thyroid cancer incidence in Fukushima despite the estimated low thyroid dose. Methods: The conversion coefficient k connecting thyroid doses estimated in UNSCEAR 2020/2021 and doses based on direct thyroid dose measurements in Chernobyl: 1 GyUN2021 = k × 1 Gy (gray), was estimated by comparing incidences and dose dependences of thyroid cancers in Fukushima and Chernobyl after nuclear disasters. Results: The ratio of the observed cases /expected cases from cancer registry: of about 60 in Fukushima prefecture, was higher than the ratios observed after the Chernobyl accident. The thyroid doses estimated by UNSCEAR were corrected by adding a baseline dose to recover the severely underestimated ingestion dose. The conversion coefficients were: k =60~70 from the comparison of the excess absolute risks (EAR) and their dose dependences in Fukushima and in Chernobyl, and k =10~180 from the comparison of excess relative risk per gray (ERR/Gy) in Fukushima with those in Chernobyl. The thyroid doses might have been underestimated by about 1/50~1/100 in UNSCEAR 2020/2021. Conclusion: The dozens-fold increase of childhood thyroid cancer cases after the Fukushima nuclear accident was found to arise from radioactive iodine exposure comparable to that in Chernobyl.

The impact of the Fukushima nuclear accident on marine biota: Retrospective assessment of the first year and perspectives

How and why did fossil fuel use change in Fukushima Prefecture before and after the Great East Japan Earthquake?

Introduction: Human beings are naturally exposed to ionizing radiation in any environment. There are two main contributors to radiation exposures from natural sources: cosmic rays, Cosmo genic radionuclides, and radioactive nuclides that originated in the earth's crust. According to the latest data provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the estimated worldwide average annual exposure to natural radiation sources is 2.4 mSv, and the most exposures are in the range of 1–13 mSv/a. There are several small areas throughout the world where people are exposed to natural radiation sources that are in excess of those considered normal background”. However, there are no specific criteria in this regards, these areas are referred to as High Natural Radiation (HNRA) areas. Ramsar is one of these areas. The natural radioactivity of Ramsar is mainly due to the presence of Ra-226 along with its daughters. The aim of this study was to determine the internal and external exposures from natural radiation sources in Ramsar, and to estimate the total annual effective dose for the people in Ramsar. Materials and Methods: In this research, the all radiation sources and exposure pathways of people living in Ramsar were investigated. The concentration of 226Ra was measured by alpha spectrometry and radon emanation in different samples including foods and drinking water, and the internal dose was estimated. In addition, the annual effective dose of exposure to gamma rays and the annual effective dose due to inhalation of radon gas were calculated for residents. Results: The mean annual effective dose due to exposure to indoor gamma rays in Ramsar was 0.66 mSv, the range was 0.3 to 48 mSv, the mean annual effective dose due to exposure to outdoor gamma rays was 0.86 mSv, and the minimum was 0.1 mSv. The mean annual effective dose of internal exposure to radon gas was 10.3 mSv and its range was from 0.9 to 232 mSv. The mean annual effective dose due to ingestion of 226Ra was found 10 µSv and its range was 1 to 81 μSv. Conclusion: Based on the results of this study, the public annual effective dose of Ramsar from exposure to natural radiation sources was 1.25 to 281 mSv, with a mean value of 12 mSv. The results of this study show that the mean value (12 mSv) is approximately 5 times greater than the worldwide mean annual exposure to natural radiation sources reported by the UNSCAER (2.4 mSv). The results obtained could be used in determining the reference levels for controlling the exposure of people and in taking preventive measures to reduce the radiation exposure of the residents. In addition, the results of this research could be useful in the study of the effect of radiation on the public health.

This is a summary of the nuclear accident at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Stations (FDNPS) on 11 March 2011 to be used as a review of the radiation effects to the thyroid and strategies of prevention. The amount of radioiodine released to the environment following the Fukushima accident was 120 Peta Becquerel, which is approximately one-tenth of that in the Chernobyl accident. Residents near the FDNPS were evacuated within a few days and foodstuffs were controlled within 1 or 2 weeks. Therefore, thyroid radiation doses were less than 100 mSv (intervention levels for stable iodine administration) in the majority of children, including less than 1 year olds, living in the evacuation areas. Because the incidence of childhood thyroid cancer increased in those residing near the site following the Chernobyl accident, thyroid screening of all children (0-18 years old) in the Fukushima Prefecture was started. To date, screening of more than 280 000 children has resulted in the diagnosis of thyroid cancer in 90 children (approximate incidence, 313 per million). Thus, although the dose of radiation was much lower, the incidence of thyroid cancer appears to be much higher than that following the Chernobyl accident. A comparison of the thyroidal consequences following the Fukushima and Chernobyl nuclear reactor accidents is discussed. We also summarize the recent increased incidence in thyroid cancer in the Fukushima area following the accident in relation to increased thyroid ultrasound screening and the use of advanced ultrasound techniques. http://links.lww.com/COE/A8.

The magnitude of dose due to the Fukushima Daiichi Accident was estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report published in April 2014. Following this, the UNSCEAR white paper, which comprises a digest of new information for the 2013 Fukushima report, was published in October 2015. Another comprehensive report on radiation dose due to the accident is the International Atomic Energy Agency (IAEA) report on the Fukushima Daiichi Accident published in August 2015. Although the UNSCEAR and IAEA publications well summarize doses received by residents, they review only literature published before the end of December 2014 and the end of March 2015, respectively. However, some studies on dose estimation have been published since then. In addition, the UNSCEAR 2013 report states it was likely that some overestimation had been introduced generally by the methodology used by the Committee. For example, effects of decontamination were not considered in the lifetime external dose estimated. Decontamination is in progress for most living areas in Fukushima Prefecture, which could reduce long-term external dose to residents. This article mainly reviews recent English language articles that may add new information to the UNSCEAR and IAEA publications. Generally, recent articles suggest lower doses than those presented by the UNSCEAR 2013 report.

The FMU and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) concluded that the high incidence of thyroid cancer after the Fukushima nuclear accident was not the result of radiation exposure, but rather might have been overdiagnosis based on the low thyroid dose estimated in the UNSCEAR 2020/2021 report. In this study, the origin of increased PTC in Fukushima was examined based on the thyroid dose estimated by UNSCEAR. The dose-response relationship of the incidence rate per person-years (PY) was analyzed for four areas in Fukushima prefecture via regression analysis. The linear response of the annual incidence rates to thyroid dose in the first six years showed that the dominant origin of childhood thyroid cancer was radiation exposure. Excess absolute risk (EAR) proportionally increased with thyroid dose, with an EAR/104 PY Gy of 143 (95%CI: 122, 165) in the second TUE (p < 0.001), which is approximately 50-100 times higher than the EAR/104 PY Gy ≒ 2.3 observed after the Chernobyl accident. This suggests an underestimation of the thyroid dose by UNSCEAR of approximately 1/50~1/100 compared with the thyroid dose for Chernobyl. The increased childhood thyroid cancer in Fukushima was found to arise from radioactive iodine exposure, which was comparable to that in Chernobyl.